1. Field of the Invention
The present invention relates to a computer system, and deals more particularly with a method, system, and computer-readable code for using a cellular phone as a network gateway in an automotive network.
2. Description of the Related Art
Consumers today have come to expect easy access to information on a multitude of topics, no matter where they happen to be at the time. Many people have cellular phones and are able to make and receive phone calls whether they are at home, in their car, shopping in a store, etc. Using a computer with a wireless modern, mobile computer users are able to access countless information services. They may connect in this manner to their company's internal network in order to work while at home or while traveling. Or, they may connect to the Internet to check the latest stock quotations, do some electronic shopping, search for information, or perform any number of other tasks.
The expectation of readily-available information does not end when the consumer steps into his vehicle. Many types of electronic information devices are becoming common in vehicles. These devices include dashboard-based information systems (including vehicle navigation systems), back-seat entertainment, on-board maintenance, etc. With a vehicle navigation system, a driver is able to obtain directions to a particular destination from his current location, all while continuing to drive. He may also receive alerts about areas where traffic is congested, and may get information about the latest weather conditions. Televisions and VCRs are commonly installed in vehicles, providing entertainment for passengers. Vehicles may even have a fax machine on board, allowing passengers to send and receive faxed information without leaving the vehicle. On-board maintenance capabilities include receiving remote diagnosis of problems when a warning light comes on without having to go to a service station. Many emergency services are also available using on-board devices. These services include: dialing "911" in response to a voice command; remotely receiving a signal that will unlock the vehicle, this signal perhaps being transmitted from the vehicle manufacturer when the driver has locked himself out; and sending a signal from the vehicle if the airbags deploy. Many of these electronic information devices need access to an external network to perform their services. Radio transmitters are typically used today for this communication; however, radio transmitters are expensive, and it is therefore undesirable to equip each individual automotive device with its own transmitter.
A cellular phone can serve as a network communication device, transmitting data either over an analog call or using digital packets. In fact, a new generation of these phones (such as the Nokia 9000, from the Nokia company) includes a fill network client protocol stack to enable applications running on the phone to communicate with Internet-based services. The protocol stacks in phones currently use TCP/IP (Transmission Control Protocol/Internet Protocol), but many are likely to be WAP-based (Wireless Application Protocol) in the fixture. However, because the cell phone is a consumer device, there is a desire to keep the software (and thus memory) footprint small in order to minimize manufacturing and retail costs.
Microsoft Corporation's AutoPC is a device for use in a vehicle, and it integrates many of the services described above. It contains the electronics of a personal computer, which the user plugs into the slot in the car dashboard where the radio and compact disk player would normally be located. This device serves as the network hub through which the vehicle's devices communicate with each other, and it is assumed to have its own wireless network capabilities through which the vehicle's devices communicate with network services located outside the vehicle. An external cell phone may be plugged into a cradle in the device for voice dialing of phone calls, but its communication capabilities are not re-used to enable the other devices to communicate with external networks. Consequently, a user must pay for one or more transmission devices (in addition to the cellular phone), and the user must obtain multiple wireless subscriptions (one for the phone, and another for the separate transmission capability in the vehicle).
U.S. Pat. No. 5,732,074, "Mobile Portable Wireless Communication System," issued Mar. 24, 1998 to CellPort Labs, Inc., describes a communications system in a vehicle which uses a cellular phone to transmit data between a remote computer and a network of devices in a car over a standardized network communications link (such as TCP/IP). In this solution, the protocol stack is built into the vehicle as part of a controller device. Thus, the cell phone is simply used as a wireless modem, to transmit and receive analog signals that must then be interpreted by the on-vehicle protocol stack on their way from and to the devices on the vehicle network. This design does not reuse the cellular phone's own communications protocol capabilities, which enable the phone to be used as a data-enabled communications device while it is detached from the vehicle.
To minimize the cost of the transmission devices and subscription services, it would be beneficial to be able to use a cellular phone not only in its normal "stand-alone" mode where it can communicate to a remote computer as a network client, but also to be able to use the phone's protocol stack and transmission capabilities to enable devices in a vehicle to communicate with an external network. The present invention enables a cellular phone, when plugged into the automotive network, to serve (together with an adapter) as a network gateway for devices on the automotive network. Further, according to the preferred embodiment, the phone retains its ability to operate as a first-class network client while plugged into the automotive network.